The invention relates to determining the location of mobile assets associated with a tag.
Determining the location of assets, such as personnel, equipment, vehicles, inventory, etc., can be important in a variety of different applications. For example, a company may wish to sound an alarm when a piece of equipment, such as a computer, is moved from one location to another, or when a person moves within a potentially dangerous area of a facility. One way to track the location of assets is to associate each asset, or group of assets, with a tag. The tag may be capable of communicating with a controller through one or more receivers to provide information used to determine the location of the tag, and thus the location of the associated asset. As one example, the tag may send a radio frequency signal that is received by one or more antennas that communicate with a controller. Based on the signal, the controller may determine where the tag is located.
A variety of methods may be used by the controller to determine the location of the tag. For example, the controller may receive a signal output by a tag at two antennas and use the signals received by each antenna to locate the tag using triangulation. However, triangulation may not be useful in situations where a signal from a tag can not be received at more than one antenna. In such cases, triangulation alone may not be used to determine the location of the tag. In addition, in some cases, a signal output by a tag may be properly received at two receivers, allowing a proper determination of the location of the tag, but improperly received at a third receiver. In such a case, inclusion of the information related to the signal received at the third receiver in the triangulation determination may prevent or confuse the process of properly identifying the location of the tag.
The present invention provides a system for determining a location of a tag. In an illustrative embodiment, at least one device is provided to communicate with a tag, e.g., the device may receive a signal sent by the tag. Information regarding communication with a reference tag is stored, processed, and/or analyzed to determine a location of a tag. As one example, information regarding the communication with the reference tag may be stored in a lookup table and used to determine the location of other tags.
In an illustrative embodiment, an asset location system is provided including at least one receiver that receives a signal from a tag, a controller that communicates with the at least one receiver, and a memory that stores data regarding previous communication between at least one receiver and a reference tag while the reference tag is in at least two different locations. The controller may determine a location of the tag based on the stored information regarding communications with the reference tag.
In another illustrative embodiment, a method for locating a tag is provided. One or more signals representing a communication with a reference tag while the reference tag is in at least two locations is received and stored. A location of a tracking tag is determined based on the stored information regarding communications with the reference tag.
In another illustrative embodiment, a method of determining a location of a tag is provided. At least one device to communicate with a tag is provided and a signal representing communication with the tag is received. A preliminary location for the tag is determined based on the signal, and the preliminary location is filtered before being used to report the tag location.
According to another illustrative embodiment, a method for developing a system for determining a location of a tag is provided. A reference tag is positioned in at least one zone, and data representing a distance from the reference tag to at least one reference point is obtained while the reference tag is in the zone. An algorithm for determining a location of a tracking tag is determined based on the obtained data.
In another illustrative embodiment, a storage medium including a set of instructions to be executed by a data processing apparatus is provided. The set of instructions includes instructions to receive a plurality of signals representing a location of a reference tag with respect to at least one reference point, instructions to analyze the plurality of signals for patterns regarding locations of the reference tag with respect to the at least one reference point, and instructions to provide a representation of the analysis of the signals to a user.
In another illustrative embodiment, a method for determining a location of a tag is provided. A tag is communicated with at at least two different receiver locations, and tag-receiver distances between the tag and the two receiver locations are determined. The location of the tag is determined based on the two tag-receiver distances.
The invention encompasses the features hereinafter fully described and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative embodiments of the invention. However, these embodiments are indicative of but a few of the numerous ways in which the principles of the invention may be employed. Other objects, advantages, and novel features of the invention will become evident from the following detailed description of the invention when considered in conjunction with the drawings.